EXPERIMENTAL INVESTIGATION OF IMPACTS OF INJECTION TIMING AND PRESSURE ON COMBUSTION AND PARTICULATE MATTER EMISSION IN A SPRAY-GUIDED GDI ENGINE

Miaomiao Zhang,Wei Hong,Fangxi Xie,Yan Su,Liwei Han,Bin Wu 한국자동차공학회 2018 International journal of automotive technology Vol.19 No.3

A detailed investigation of the impact of injection timing and injection pressure on combustion and particles of a spray-guided GDI engine was conducted, under different engine operating conditions. The results indicated that, more proportion of large particles were emitted when increasing engine load, and the peak of accumulation mode particles moved toward smaller size when rising engine speed. With retarding the injection timing, the in-cylinder pressure and heat release rate rose first and then dropped at 2000 rpm, but they continuously rose at lower or higher speed conditions. The total particles concentration curves at all cases showed a trend of U-shape, and the corresponding timing of the lowest particles concentration advanced as the engine speed or load increased. The minimum value of emitted particles first rose and then fell when increasing load at 2000 rpm conditions, and it continuously rose when increasing speed at 40 Nm conditions. Generally, injection pressure did no sensitively affect combustion process except that it showed a relatively strong impact at low load conditions. However, particulate matter could be effectively inhibited by elevating fuel pressure from 5.5 to 11.5 MPa at all cases. In detail, the total particles concentration continuously fell at low speed and mid speed-high load cases, but it showed a rose trend when further increase fuel injection pressure at mid speed-low load and high-speed conditions.

Numerical and experimental study of cone-headed projectile entering water vertically based on MMALE method

Cao Miaomiao,Shao Zhiyu,Wu Siyu,Dong Chaochao,Yang Xiaotian 대한조선학회 2021 International Journal of Naval Architecture and Oc Vol.13 No.1

The water entry behaviors of projectiles with different cone-headed angles were studied numerically, experimentally and theoretically, mainly focusing on the hydrodynamic impact in the initial stage. Based on MMALE algorithm, it was proposed a formula of impact deceleration, which relied on the initial entry velocity and cone-headed angle. Meanwhile, in order to verify the validity of the simulation model, experiments using accelerometer and high-speed camera were carried out, and their results were in a good agreement with simulation results. Also, theoretical calculation results of cavity diameter were compared with experiments and simulation results. It was observed that the simulation method had a good reliability, which would make forecast on impact deceleration in an engineering project.

Development of Recombinase Polymerase Amplification Combined with Lateral Flow Strips for Rapid Detection of Cowpea Mild Mottle Virus

Xinyang Wu,Shuting Chen,Zixin Zhang,Yihan Zhang,Pingmei Li,Xinyi Chen,Miaomiao Liu,Qian Lu,Zhongyi Li,Zhongyan Wei,Pei Xu 한국식물병리학회 2023 Plant Pathology Journal Vol.39 No.5

Cowpea mild mottle virus (CPMMV) is a global plant virus that poses a threat to the production and quality of legume crops. Early and accurate diagnosis is essential for effective managing CPMMV outbreaks. With the advancement in isothermal recombinase polymerase amplification and lateral flow strips technologies, more rapid and sensitive methods have become available for detecting this pathogen. In this study, we have developed a reverse transcription recombinase polymerase amplification combined with lateral flow strips (RT-RPA-LFS) method for the detection of CPMMV, specifically targeting the CPMMV coat protein (CP) gene. The RT-RPA-LFS assay only requires 20 min at 40°C and demonstrates high specificity. Its detection limit was 10 copies/μl, which is approximately up to 100 times more sensitive than RT-PCR on agarose gel electrophoresis. The developed RT-RPA-LFS method offers a rapid, convenient, and sensitive approach for field detection of CPMMV, which contribute to controlling the spread of the virus.

Effect of Solid Particles on Cavitation and Lubrication Characteristics of Upstream Pumping Mechanical Seal Liquid Membrane

Chen, Huilong,Sun, Dongdong,Wu, Yuanzheng,Chen, Miaomiao,Zhang, Peilin Korean Society for Fluid machinery 2017 International journal of fluid machinery and syste Vol.10 No.4

In order to investigate the effect of solid particles on the cavitation characteristics and lubricating properties of the micro-gap liquid film in Upstream pumping mechanical seals,the Eulerian multiphase flow model was used to simulate the liquid film with different diameter and volume fraction of solid particles to analyze the influence of the particles on the distribution of vacuole, opening force and friction torque of the film under different working conditions. The results showed that the particles have an inhibitory effect on the cavitation, and the cavitation area and the volume fraction of the bubbles were both decreased.The cavitation area increased with the increase of particle diameter, which indicated that the inhibition of cavitation was weakened with the increase of particle diameter. The cavitation area decreased with the increase of the particle volume fraction, and the volume fraction increased the cavitation inhibition effect. The presence of particles improved the opening force of liquid film to a certain extent and increased with the increase of particle volume fraction, but the effect of particle diameter on opening force was different under different rotating speed and different medium pressure.The friction torque did not change obviously with the particle diameter,and decreased only slightly with the increase of the particle volume fraction.In the working condition range, the cavitation degree is not related to the pressure of the medium, but increases with the increase of the rotational speed, and the cavitation area and volume fraction of bubbles Were significantly decreased when there were solid particles.

Identification of AMPK activator from twelve pure compounds isolated from Aralia Taibaiensis: implication in antihyperglycemic and hypolipidemic activities

Li, Yuwen,Park, Jongsun,Wu, Yin,Cui, Jia,Jia, Na,Xi, Miaomiao,Wen, Aidong The Korean Society of Pharmacology 2017 The Korean Journal of Physiology & Pharmacology Vol.21 No.3

The root bark extract of Aralia taibaiensis is used traditionally for the treatment of diabetes mellitus in China. The total saponin extracted from Aralia Taibaiensis (sAT) has effective combined antihyperglycemic and hypolipidemic activities in experimental type 2 diabetic rats. However, the active compounds have not yet been fully investigated. In the present study, we examined effects of twelve triterpenoid saponins on AMP-activated protein kinase (AMPK) activation, and found that compound 28-O-${\beta}$-D-glucopyranosyl ester (AT12) significantly increased phosphorylation of AMPK and Acetyl-CoA carboxylase (ACC). AT12 effectively decreased blood glucose, triglyceride (TG), free fatty acid (FFA) and low density lipoprotein-cholesterol (LDL-C) levels in the rat model of type 2 diabetes mellitus (T2DM). The mechanism by which AT12 activated AMPK was subsequently investigated. Intracellular ATP level and oxygen consumption were significantly reduced by AT12 treatment. The findings suggested AT12 was a novel AMPK activator, and could be useful for the treatment of metabolic diseases.

Identification of AMPK activator from twelve pure compounds isolated from Aralia Taibaiensis: implication in antihyperglycemic and hypolipidemic activities

Yuwen Li,박종선,Yin Wu,Jia Cui,Na Jia,Miaomiao Xi,Aidong Wen 대한약리학회 2017 The Korean Journal of Physiology & Pharmacology Vol.21 No.3

The root bark extract of Aralia taibaiensis is used traditionally for the treatment of diabetes mellitus in China. The total saponin extracted from Aralia Taibaiensis (sAT) has effective combined antihyperglycemic and hypolipidemic activities in experimental type 2 diabetic rats. However, the active compounds have not yet been fully investigated. In the present study, we examined effects of twelve triterpenoid saponins on AMP-activated protein kinase (AMPK) activation, and found that compound 28-O-β-D-glucopyranosyl ester (AT12) significantly increased phosphorylation of AMPK and Acetyl-CoA carboxylase (ACC). AT12 effectively decreased blood glucose, triglyceride (TG), free fatty acid (FFA) and low density lipoprotein-cholesterol (LDL-C) levels in the rat model of type 2 diabetes mellitus (T2DM). The mechanism by which AT12 activated AMPK was subsequently investigated. Intracellular ATP level and oxygen consumption were significantly reduced by AT12 treatment. The findings suggested AT12 was a novel AMPK activator, and could be useful for the treatment of metabolic diseases.

Identification of AMPK activator from twelve pure compounds isolated from <i>Aralia Taibaiensis</i>: implication in antihyperglycemic and hypolipidemic activities

Yuwen Li,Jongsun Park,Yin Wu,Jia Cui,Na Jia,Miaomiao Xi,Aidong Wen 대한생리학회-대한약리학회 2017 The Korean Journal of Physiology & Pharmacology Vol.21 No.3

The root bark extract of <i>Aralia taibaiensis</i> is used traditionally for the treatment of diabetes mellitus in China. The total saponin extracted from <i>Aralia Taibaiensis</i> (sAT) has effective combined antihyperglycemic and hypolipidemic activities in experimental type 2 diabetic rats. However, the active compounds have not yet been fully investigated. In the present study, we examined effects of twelve triterpenoid saponins on AMP-activated protein kinase (AMPK) activation, and found that compound 28-O-β-D-glucopyranosyl ester (AT12) significantly increased phosphorylation of AMPK and Acetyl-CoA carboxylase (ACC). AT12 effectively decreased blood glucose, triglyceride (TG), free fatty acid (FFA) and low density lipoprotein-cholesterol (LDL-C) levels in the rat model of type 2 diabetes mellitus (T2DM). The mechanism by which AT12 activated AMPK was subsequently investigated. Intracellular ATP level and oxygen consumption were significantly reduced by AT12 treatment. The findings suggested AT12 was a novel AMPK activator, and could be useful for the treatment of metabolic diseases.

Effect of Solid Particles on Cavitation and Lubrication Characteristics of Upstream Pumping Mechanical Seal Liquid Membrane

Huilong Chen,Dongdong Sun,Yuanzheng Wu,Miaomiao Chen,Peilin Zhang 한국유체기계학회 2017 International journal of fluid machinery and syste Vol.10 No.4

In order to investigate the effect of solid particles on the cavitation characteristics and lubricating properties of the micro-gap liquid film in Upstream pumping mechanical seals, the Eulerian multiphase flow model was used to simulate the liquid film with different diameter and volume fraction of solid particles to analyze the influence of the particles on the distribution of vacuole, opening force and friction torque of the film under different working conditions. The results showed that the particles have an inhibitory effect on the cavitation, and the cavitation area and the volume fraction of the bubbles were both decreased. The cavitation area increased with the increase of particle diameter, which indicated that the inhibition of cavitation was weakened with the increase of particle diameter. The cavitation area decreased with the increase of the particle volume fraction, and the volume fraction increased the cavitation inhibition effect. The presence of particles improved the opening force of liquid film to a certain extent and increased with the increase of particle volume fraction, but the effect of particle diameter on opening force was different under different rotating speed and different medium pressure. The friction torque did not change obviously with the particle diameter, and decreased only slightly with the increase of the particle volume fraction. In the working condition range, the cavitation degree is not related to the pressure of the medium, but increases with the increase of the rotational speed, and the cavitation area and volume fraction of bubbles Were significantly decreased when there were solid particles.

Observational studies of traditional Chinese medicine may provide evidence nearly consistent with the randomized controlled trials: A meta-epidemiological study

Haiqi Song,Nian Li,Wenjie Yang,Miaomiao Wu,Xiaoyang Liao,Yonggang Zhang 한국한의학연구원 2022 Integrative Medicine Research Vol.11 No.4

Background In traditional Chinese medicine (TCM) field, the benefits of observational studies was more significant. Whether the evidence from observational studies agreed with RCTs in the field of TCM was still unclear. Methods A meta-epidemiological study was conducted. Meta-analyses and systematic reviews including cohort studies and case-control studies of TCM were included. Ratio of odds ratio (ROR) of randomized controlled trials and observational studies were calculated individually and intercomparisons were conducted by pool analysis. Results A total of 11 studies and 30 outcome pairs were included in the pool analysis. Using results from the observational studies as the reference group, the polled ROR comparing randomized controlled trials with observational studies was 1.23 (95% confidence interval 1.05 to 1.44, and 95% prediction interval 0.90 to 1.68). The ROR by subgroup analysis were 1.15 (95% confidence interval 0.96 to 1.38; 95% prediction interval 0.95 to 1.39) and 1.12 (95% confidence interval 0.86 to 1.46; 95% prediction interval 0.51 to 2.47) for cohort studies and case-control studies, respectively. Conclusions There is difference in pooled results between randomized controlled studies and observational studies on TCM. However, the prediction interval shows the difference is small, which suggests observational studies of TCM can be included in data analysis to provide evidence for TCM. Future studies are needed to verify the above conclusion.